IS 12622:1989 i Indian Standard ( Reaffirmed 2006 ) MEDICAL THERMOMETERS FOR HYPOTHERMIA, SUBNORMAL RANGE SPECIFICATION UDC 536'512 : 616 - 073'65 @ BIS 1990 BUREAU MANAK OF BHAVAN, INDIAN STANDARDS ZAFAR MARG 9 BAHADUR SHAH -NEW DELHI 110002 May 1990 Price Group 2 Laboratoryware and Related Apparatus Sectional Committee, CDC 33 FOREWORD This Indian Standard was adopted by the Bureau of Indian Standards on 16 January 1989, after the draft finalized by the Laboratoryware and Related Apparatus Sectional Committee had been approved by the Chemical Division Council. -In order to meet the medical requirements for measuring the body temperatares under the condition of hypothermia and cryotherapy, the committee decided to formulate a separate standard on the subject. It differs from the normal clinical thermometer in that it covers a wider range of temperature from 25 to 40°C In those cases, where the ambient temperature is likely to be higher than the body temperature ( as in hypothermia ), it is recommended that the temperature be read after dipping the thermometer in ice cold water immediately after removing from the human body. In the formulation of this standard, considerable assistance has been derived from BS 691 : 1987 `Specification for solid-stem clinical maximum thermometers ( mercury-in-glass )`, issued by the British Standards Institution, UK. For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance~with IS 2 : 1960-`Rules for rounding off numerical values ( revised J'. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard. IS 12622 : 1989 Indian Standard MEDICAL THERMOMETERS FOR HYPOTHERMIA, SUBNORMAL RANGE SPECIFICATION 1 SCOPE /TOP This standard prescribes requirements and methods of sampling and test for solid stem medical thermometers for hypothermia having maximum indicating device for the measurement of deep body temperature of human beings. 2 REFERENCES ROUNDED OFF _/---BORE The following Indian Standards adjuncts to this standard: IS No. IS 2627 : I979 Title are necessary Glossary of terms relating to thermometers liquid-in-glass ( jrst revision ) Specification for liquid-in-glass solid-stem reference thermometers (first revision ) Methods of calibrating in-glass thermometers liquid- IS 4825 : 1982 IS 6274 : 1971 3 TERMINOLOGY For the purpose of this standard, the definitions given in IS 2627 : 1979 shall apply. 4 TYPE The thermometer shall be of mercury-in.glass type with a solid stem of `lens-front' section and shall be provided with an enamel back. 5 TEMPERATURE SCALE ,r CONSTRICTION The thermometers shall be graduated in degree Celsius ("C ). The thermometers shall have a range from 25 to 40°C. 6 IMMERSION The thermometers shall be caliberated vertical immersion. 7 REQUIREMENTS 7.t Pattern The stem and graduations of the thermometer shall be as shown in Fig. I. The bulb shall be cylindrical and shall -be of `stubby' pattern. 1 for total FIG. I MEDICAL THERMOMETER FOR HYPOTHBRMIA- SUBNORMALRANGE 7.2 Materia!s 7.2.1 Glass Tubing The thermometers shall be made from capillary glass tubing and the bulb tubing having coefficient of linear thermal expansion of 8'5 & O-3 x lO-6 x k-l in the-range of 0 to 100°C. 7.2.2 Thermmneiric The thermometric cury. Liquid liquid shall be pure, dry mer- IS 12622 : 1989 7.3 Construction 7.3.1 Stem 7.6 Graduation and Figuring scale shall be subdivided The stem shall be in alignment with the bulb. 7.3.1.1 The free end of rhe stem shall be finished smooth, preferably hemispherical in shape, as shown in Fig. 1. 7.3.2 Maximum Indicating Device ( Constrictioil ) 7.6.1 The thermometer .n 0'2°C intervals as shown in Fig. 1. 7.6.2 The graduation lines shall be at right angles .o the axis of the thermometer. 7.6.3 All graduation lines shall be of equal and uniform thickness of not more than 0'15 mm. 7.6.4 The pattern of graduation shall be as follows: a) Every fifth graduation line ( about 2 mm ). and figuring The thermometer shall have a maximum indicating device ( constriction ), constructed in the capillary, between the mercury bulb and the scale in order to prevent the mercury in the stem from returning to the bulb on cooling. 7.3.2.1 The maximum indicating device shall pass the hardness test prescribed in Annex A, when an acceleration of 600 m/s2 is applied at the closed end of the bulb for a Feriod of at least 2 minutes. 7.3.3 Locater A locater ( for example, an arrow or a dot or a square ) may be provided on the stem before the start of the scale to facilitate reading. 7.3.4 Bulb The bulb shall be hemispherical at the tip. The diameter of bulb and that of the joint of the bulb with the stem, shall nowhere exceed that of the stem. The joint shall be smooth and regular. 7.4 Capillary ? Tube line shall be a long b) On every twenty-fifth line there shall be a figure. 7.6.5 When the thermometer is held in a vertical 2osition and viewed from the front the left hand ends of all the graduation lines shall lie on an imaginary vertical line ( see Fig. 1 ). 7.6.6 The figures shall be placed to the right of the axis in such a way that the extension of the line to which they refer, wou!d bisect them. The figures shall be placed parallel to the axis of the thermometer. 7.6.7 A distinguishing mark ( for example, an arrow or a dot or a square ) shall bz marked/ etched at 37*O"C to prominently indicate the `normal temperature'. 7.6.8 All graduation lines and tigures shall bc clearly and permanently marked or etched on the stem and filled with a pigment, and the marking shall pass the test for permanency prescribed in Annex B. NOTE-The pigment may be black, red, blue as agreed to between the purchaser supplier. green or and the by he capillary tube shall be smooth and uniform. 7.5 Dimensions The dimensional and scale requirements for clinical thermometers shall be as given in Table 1. Table 1 Dimensional and Scale Requirements for Solid Stem Medical Thermometers ( Sl. No. (1) 7.6.9 Each end of the scale shall be extended five divrsions beyond the limit of the scale. 8 PERFORMANCE 8.1 Appearance REQUIREMENTS for Hypothermia, Range Subnormal Clause 7.5 ) -I_ Requirement (3) Particulars (2) When heated to 40'0°C or so, the mercury column shall look like a rectangular strip of uniform width, with clarity and brightness throughout. NOTE-This test takes care of all visual for example, twist in the glass, aberrations, ness, divitrification, etc. defects, cloudi- i) Scale range, "C ii) iii) iv) v) vi) vii) viii) ix) Smallest scale division, "C Overall length, mm Scale length, mm, Min External diameter of stem, mm Bulb length, mm, Max External diameter of bulb, mm Distance from top of the constriction to 25°C mark, mm, Min Distance from the highest graduation line to the top of the ste, mm, Mln 2.54 to 40.0 0.2 100 to 115 55 4.5 to 5.5 9 2 to 3 10 8.2 Ageing and Accuracy Medical thermometers shall be adequately aged to ensure that their accuracy measured by the method prescribed in Annex C, shall be within rJI:0'2°C for at least one year after the first official verification. 8.3 Time of Response The time of response of medical Ihcrmometers 2 as 8 IS 12622 : 1989 checked by the method prescribed shall not exceed 8.0 seconds. in Annex D, 10 SAMPLING 10.1 Lot All thermometers of the snmc type, in a single consignment and produced under similar conditions of manufacture, shall constitute a lot. 10.2 For permanence of marking, the number of thcrmometcrs to be tested shall depend on the size of the lot and shall be in accordance with Table 2. All the thermometers so tested shall pass the test. 10.3 For remaining characteristics given in the specification, all thermometers in the lot shall be tested and shall conform to each of the corresponding requirements. Table 2 Scale of Sampling ( CIUUSC 10.2 ) Sample Size n 500 1000 3000 5 8 13 20 32 8.4 When the temperature is rising very slowly, at a uniform rate, the jumping of the meniscus of the thermometric liquid shall not exceed one-half of the smallest scale. 9 MARKING 9.1 Msrking Each medical thermometer shall be legibly and indelibly marked cm its stem with the following: a) The letter `"C' near the top of the scale, b) Indicating the source of manufacture, c) A code number to trace the batch of manufacture, d) Month and year of mani!facture, and e) A recognized trade-mark of the verifying showing the year of initial authority verification. 9.2 Packing Medical thermometers shall be securely packed, and collectively, in any manner individually acceptable to the purchaser so as to minimize the risk of damage in handling. . AND PACKING Number of Thermometers in the Lot N up to 501 to 1001 to 3-001 to 10 000 10 001 and above ANNEX A ( Clause 7.3.2.1 TEST A-l APPARATUS A-I.1 Centrifuge A certrifuge with radial arms 15C:mni each shall be used. Each arm shall be provided with a pocket for keeping one or more thermometers. The speed of the centrifuge shall be either fixed or adjustable to 600 rpm. A-2 PROCEDURE A-2.1 Place the thermometers for some time water at a temperature between 40 and 41°C. A-2.2 Then put them in the pockets in FOR HARDNESS OF MAXIMUM ) INDICATING DEVICE centrifuge, bulbs facing outwards, that is, away from the~axis of the centrifuge while in rotation. A-2.3 Let the centrifuge work steadily at its correct speed for at least 2 minutes. Then stop it. A-2.4 Take the thermometers out of the and observe the mercury column. pockets A-2.5 Thermometers shall be taken as having satisfied the requirements of this test if the mercury column rests below or at 24°C mark. IMPORTANT - It is necessary temperature of the that the rovm does not exceed 23°C during the test. ANNEX TEST R-1 PROCEDURE B-I.I Place the rhermometers in a 5 percent ( );I,`v) solution of 17henol in water maintnlned at 37.0 -& 0'5°C for a l`eriod of 20 minutes. 3 FOR PERMANENCY B ( Clause 7.6.8 1 OF MARKING dry with a piece of B-1.2 ._ Wipe the . thermometer soft cloth and examine. B-1.3 The thermometers shall bc considered to have passed the test, if after this treatment, the marking does not peel off anywhere. IS 12622 : 1989 ANNEX ( TEST C-l APPARATUS C- 1.1 Comparator Bath Conlparator bath, either screw type or bubbler type, as prescribed in IS 6274 : 1971 shall be used. Clu11se C 8.2 ) ACCURACY C-2 PROCEDURE After preliminary check of the medical carry out the accuracy test in thermometers'. accordance wtth 6.2 of IS 6274 : 1971 at 26.0 f 0'5°C 37'0 f 0'5°C and 40'0 f 0.5"C, respectively. c-2.2 The thermometers c-2.1 FOR C-1.2 Reference Thermometer Calibrated reference thermometers 1982 ) shall be used. ( ,rep IS 4825 : shall be considered to have passed this test if the accuracy so determined lies within the limits prescribed in 8.2. ANNEX D ( Clause 8.3 ) TEST FOR TIME D-l APPARATUS OF RESPONSE NOTE -Centrifuge mentioned used for this purpose, if required. under A-l.1 may b Apparatus same as in C-l.1 and used provided that some automatic is made to switch off stirring at C-1.2 shall be arrangement the instant the bulbs of thermometers under test touch the water surface and to switch it on again immediately after the thermometers are taken out of the water. D-2 PROCEDURE D-2.1 Set the comparator bath at a temperature of 40'0 f 0'5°C. -Note the temperature- on the reference thermometer. D-2.2 Shake down the thermometers under test to maximum extent D-2.3 Plunge the thermometers into the bath up to 25°C mark. Take out suddenly after 7 5 to 8'0 seconds, wipe and dry. Take their readings. D-2.4 The thermometers shall be considered. to have passed this test if they indicate temperature within & 0'1°C of the comparator bath temperature noted in D-2.1. IMPORTANT - It is necessary that the room temperature does not exceed 23'0°C during the test. Standard Mark The use of the Standard Mark is governed by the provisions of the Bureau of Indian Act, 1986 and the Rules and Regulations made thereunder. 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